zoukankan      html  css  js  c++  java
  • 产生有序的全局唯一Id

    //利用时间和Guid作为种子产生随机数
    private string GenerateUniqueID()
    {
          System.Text.StringBuilder sb = new System.Text.StringBuilder();
          string str1 = DateTime.Now.ToString("yyyyMMddHHmmss");
          Random d = new Random(Guid.NewGuid().GetHashCode());
          string str2 = d.Next(10000, 100000).ToString();
          return sb.Append(str1).Append(str2).ToString();
     }
      
           //利用时间和RNGCryptoServiceProvider产生
            public static string GenerateOrderNumber()
            {
                string strDateTimeNumber = DateTime.Now.ToString("yyyyMMddHHmmssms");
                string strRandomResult = NextRandom(1000, 1).ToString();
                return strDateTimeNumber + strRandomResult;
            }
    
            /// <summary>
            /// 参考:msdn上的RNGCryptoServiceProvider例子
            /// </summary>
            /// <param name="numSeeds"></param>
            /// <param name="length"></param>
            /// <returns></returns>
            private static int NextRandom(int numSeeds, int length)
            {
                // Create a byte array to hold the random value.  
                byte[] randomNumber = new byte[length];
                // Create a new instance of the RNGCryptoServiceProvider.  
                System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider();
                // Fill the array with a random value.  
                rng.GetBytes(randomNumber);
                // Convert the byte to an uint value to make the modulus operation easier.  
                uint randomResult = 0x0;
                for (int i = 0; i < length; i++)
                {
                    randomResult |= ((uint)randomNumber[i] << ((length - 1 - i) * 8));
                }
                return (int)(randomResult % numSeeds) + 1;
            }
    

      

  • 相关阅读:
    使用PowerDesigner 15对现有数据库进行生成图表结构
    dynamic的使用
    js 字符串的replace() 方法和实现replaceAll() 方法
    学习新属性 requestAnimationFrame
    Mapbox 地图样式规范
    Emmet插件使用方法总结
    js循环遍历性能
    lunix部署其前端项目常见报错
    componentWillMount和componentDidMount的区别
    控制浏览器禁止缓存
  • 原文地址:https://www.cnblogs.com/jeffrey77/p/6274454.html
Copyright © 2011-2022 走看看